Are talking about the switch the key goes in or the electric switch on the bottom of the column that has the electrical plugs in it?
the key one I don't think could be the problem, but the one the electrics plug in could be, do you feel the spring when you turn it to start? if not you may have it in the wrong position or a new defective switch, both are possible.
Technology is great when it works,
and one big pain in the ass when it doesn't
Detroit iron rules all the rest are just toys.